[mle] request network data on child reattach after reboot (#2466)
[mle] request network data on child reattach after reboot (#2466)

This commit adds a Network Data TLV request to the MLE Child Update Request
message when trying to resynchronize with a parent after reset.  This
eliminates the need for an MLE Data Request/Response exchange following the
MLE Child Update Request/Response exchange.
LeZhang2016/openthread,srickardti/openthread,turon/openthread,turon/openthread,lanyuwen/openthread,georgecpr/openthread,bukepo/openthread,abtink/openthread,mszczodrak/openthread,chshu/openthread,pvanhorn/openthread,chshu/openthread,mszczodrak/openthread,georgecpr/openthread,mszczodrak/openthread,srickardti/openthread,gandreello/openthread,chshu/openthread,chshu/openthread,bukepo/openthread,abtink/openthread,mszczodrak/openthread,chshu/openthread,mszczodrak/openthread,georgecpr/openthread,erja-gp/openthread,lanyuwen/openthread,erja-gp/openthread,bukepo/openthread,pvanhorn/openthread,gandreello/openthread,erja-gp/openthread,bukepo/openthread,georgecpr/openthread,jwhui/openthread,mszczodrak/openthread,georgecpr/openthread,librasungirl/openthread,abtink/openthread,lanyuwen/openthread,erja-gp/openthread,openthread/openthread,gandreello/openthread,lanyuwen/openthread,abtink/openthread,openthread/openthread,pvanhorn/openthread,georgecpr/openthread,erja-gp/openthread,turon/openthread,srickardti/openthread,pvanhorn/openthread,LeZhang2016/openthread,LeZhang2016/openthread,lanyuwen/openthread,gandreello/openthread,librasungirl/openthread,pvanhorn/openthread,librasungirl/openthread,pvanhorn/openthread,jwhui/openthread,openthread/openthread,jwhui/openthread,librasungirl/openthread,erja-gp/openthread,lanyuwen/openthread,chshu/openthread,LeZhang2016/openthread,LeZhang2016/openthread,LeZhang2016/openthread,srickardti/openthread,turon/openthread,jwhui/openthread,gandreello/openthread,gandreello/openthread,openthread/openthread